Extend your WindTrak 10 Sport or WindTrak 15 vane away from masthead obstructions. The 13" (33 cm) arm comes with hardware to allow for side or top mounting and offset angles up to 20 degrees. Mount on the back of the mast for easier viewing from the cockpit. Can be used with the Windex Light. Length 13 inches (33 cm). Weight 3.2 oz (90 g).